Some of Puerto Rico's tourist booklets encourage the visitor to "explore beyond the shore." One of the ways to explore is by taking some of the twisting mountain roads. The "Luis Munoz Marin" panoramic route, named after a former governor of the island, crosses the length of Puerto Rico from west to east, and would take a few days to cover well.
I started on the western side near Mayaguez and continued to the areas directly north of Ponce, which was manageable in an afternoon. For me, the highlights of the trip were the cute churches and other buildings, the quiet, the abundant plant life, and the occasional view of coffee fields and valleys.
I even ran into a young man on horseback.
I stopped at a local bar in the area between Maricao and Yauco and was told that a great time to visit Puerto Rico is during Christmas time, when the whole interior explodes in music and celebrations.
See my webpage on Puerto Rico at http://www.latinandcaribbeantravel.com/puertorico.html